This invention relates to the preparation of cis-1,2-trans-4-cyclohexane tricarboxylic acids and esters thereof.
It is known that olefins may be carboxylated under relatively mild conditions in the presence of palladium-phosphine complexes. See, for example, Fenton, J. Org. Chem., 38 3192-3198 (1973); Bittler et al., Angew. Chem. internat. Edit., 7, 329-335 (1968); and James et al. J.A.C.S., 98, 1810-1823 (1976).
U.S. Pat. No. 3,444,237 to Jaffe dated May 13, 1969 is directed to a process for hydrogenating trimellitic acid to produce a mixture of the isomers of 1,2,4-cyclohexane tricarboxylic acids. This process uses a metallic ruthenium catalyst. U.S. Pat. No. 3,437,676 to Kutepow et al. dated Apr. 8, 1969 teaches that an alkene is reacted with water or phenol to produce a carboxylic acid or ester in the presence of a palladium complex.
None of these teachings address the issue of stereo selectivity.